03Where does power flow, and why do prices split?
Germany's wind is in the north, its demand in the south
Why does electricity made on the coast so often fail to reach the industrial south?
Germany's wind sits in the north and its demand in the south, joined by one national price and a grid that cannot always carry the power between them. It has about 71 GW of onshore wind and 11 GW offshore installed, against roughly 115 GW of solar, according to Germany's register of power plants (the Marktstammdatenregister).
When the north–south lines are full, some of that northern wind is turned down because the grid cannot move it, and the lost output is paid for.
Sources: installed capacity from Germany's register of power plants, the Marktstammdatenregister (MaStR, © Bundesnetzagentur, the grid regulator); regional generation and load from SMARD; curtailment from netztransparenz; negative-price hours from ENTSO-E day-ahead prices.
Installed wind capacity by county (Landkreis), from the plant register (MaStR), with the largest plants and major demand centres. Capacity clusters in the windy north; demand sits in the southern and western cities.
This map shows installed capacity (MW): what could generate. A high-capacity county still generates little on a calm or dark day. Capacity shows where the build-out happened; the time-series panels show what it does.
Demand centres are shown using population as a proxy; Germany doesn't publish electricity consumption county by county at this cadence. Read them as where people and activity are; nobody meters the load at this level.
Generation minus load per control area, the part of the grid one transmission operator runs; Germany has four. 50Hertz and TenneT (north) produce more than they use; Amprion and TransnetBW (south and west) use more than they produce. When the corridor between them is full, the grid operators pay northern plants to turn down and southern ones to turn up (redispatch), and clean energy gets curtailed.
Net balance is generation minus load per control area (SMARD), averaged over the last 12 months in German time (CET/CEST). The north–south bottleneck lies inside the single bidding zone of Germany and Luxembourg (DE-LU), so it never appears in cross-border flows or zonal prices; the redispatch and curtailment volume shows it. Curtailment is a regional volume from the four grid operators (netztransparenz), 1–3 day lag.
Two of the four control areas, 50Hertz and TenneT, make most of Germany's wind; TenneT's area runs from the North Sea to Bavaria, so it also makes the largest share of the solar. The second chart shows an average day in each area for one month.
High-wind months bring both curtailment and negative prices, so the price alone doesn't signal that the south is short or the north is long.
wind long, would clear cheaper
demand heavy, would clear dearer
Germany and Luxembourg are a single bidding zone: one wholesale electricity price for the whole area, even when the grid physically can't move power from the windy north to the industrial south. When the link is full, cheap northern wind can't reach southern demand, so the grid operators pay some plants to turn down and others to turn up (redispatch), and the cost lands on consumers' network charges.
Some economists argue this is the case for splitting Germany into smaller bidding zones, so prices would signal scarcity where the grid is constrained and pull investment to where it's needed. Others argue a single zone preserves price solidarity between regions, avoids structurally higher prices in the south, and keeps the market simpler and more liquid. Wattlas takes no side: it shows the physical mismatch the debate is about.
Curtailment here means wind and solar the grid operators told to turn down because the grid could not carry it. The four German grid operators measure it and report it for the region as a whole (netztransparenz), with a 1–3 day lag, and it is paid for.
Questions
If Germany has one electricity price, where does the north–south bottleneck show up?
In the grid. Germany and Luxembourg share one bidding zone, an area with one wholesale price, so the day-ahead price is the same in Hamburg and Munich. When the lines between north and south are full, the bottleneck shows up as redispatch: grid operators pay for power to be turned down in the north and up in the south.
What happens to wind power that cannot get south?
Some of it is turned down. Wind farms in the north are curtailed, meaning switched off because the grid cannot carry their power, and their operators are paid for the output they lose. That payment and the cost of running plants in the south instead are recovered through the network charges on electricity bills.
How these numbers are made: Each control area's share of wind and solar.
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